Many industries have been working for the past few decades to find replacements for the ozone depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). The CFCs and HCFCs have been employed in a wide range of applications, including their use as aerosol propellants, refrigerants, cleaning agents, expansion agents for thermoplastic and thermoset foams, heat transfer media, gaseous dielectrics, fire extinguishing and suppression agents, power cycle working fluids, polymerization media, particulate removal fluids, carrier fluids, buffing abrasive agents, and displacement drying agents. In the search for replacements for these versatile compounds, many industries have turned to the use of hydrofluorocarbons (HFCs).
The HFCs do not contribute to the destruction of stratospheric ozone, but are of concern due to their contribution to the “greenhouse effect”, i.e., they contribute to global warming. As a result of their contribution to global warming, the HFCs have come under scrutiny, and their widespread use may also be limited in the future. Thus, there is a need for chemical compounds that have both low ozone depleting potentials (ODPs) and low global warming potentials (GWPs).
One such useful HFC that has a low GWP is 2,3,3,3-tetrafluoro-1-propene (HFC-1234yf). It is useful as a refrigerant and blowing agent. It is prepared by many methods, one of which is from the following process:                (1) (CX2═CCl—CH2X or CX3—CCl═CH2 or CX3—CHCl—CH2X)+HF→2-chloro-3,3,3-trifluoropropene (HCFO-1233xf)+HCl in a vapor phase reactor charged with a solid catalyst;        (2) 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf)+HF→2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) in a liquid phase reactor charged with a liquid hydrofluorination catalyst; and        (3) 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) 2,3,3,3-tetrafluoropropene (HFO-1234yf) in a vapor phase reactor.        
Thus, 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) is an intermediate in the process of making 2,3,3,3-tetrafluoropropene (HFO-1234yf). HCFC-1233xf is obtained by the dehydrochlorination of HCFC-243db, the product of the present process.
There have been various methods for preparing HCFC-243db, such as chlorination of 3,3,3-trifluoro-1-propene (HFO-1243zf) with UV light or at high temperatures or in the liquid phase without catalyst. However, there are many problems associated with these methods. The approach with UV light is less selective and difficult to scale-up to a commercial process and the reaction in the liquid phase without a catalyst is very slow and needs to be run at high temperature. Nevertheless, even under these conditions, tar is also formed.
Thus there is a need in the art for a new process to prepare HCFC-243db that does not suffer from the inadequacies of the prior art. The present invention overcomes these problems.